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Title: Production of uranium dioxide

Abstract

A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF/sub 6/) to ceramic-grade uranium dioxide (UO/sub 2/) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF/sub 6/ with steam in a first fluidized bed, preferably at about 550/sup 0/C, to form solid intermediate reaction products UO/sub 2/F/sub 2/, U/sub 3/O/sub 8/ and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF/sub 4/). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630/sup 0/C. The second intermediate reaction product including uranium dioxide (UO/sub 2/) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650/sup 0/C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein amore » mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO/sub 2/ and increase the oxygen-uranium ratio to about 2.25.« less

Inventors:
; ;
Publication Date:
OSTI Identifier:
5386597
Patent Number(s):
US 4053559
Application Number:
TRN: 78-002511
Assignee:
Westinghouse Electric Corp.
Resource Type:
Patent
Resource Relation:
Patent File Date: Filed date 14 Jun 1976
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 36 MATERIALS SCIENCE; URANIUM DIOXIDE; PRODUCTION; CONVERSION; FLUIDIZED BED; HYDROGEN; REDUCTION; STEAM; URANIUM HEXAFLUORIDE; ACTINIDE COMPOUNDS; CHALCOGENIDES; CHEMICAL REACTIONS; CRYOGENIC FLUIDS; ELEMENTS; FLUIDS; FLUORIDES; FLUORINE COMPOUNDS; HALIDES; HALOGEN COMPOUNDS; NONMETALS; OXIDES; OXYGEN COMPOUNDS; URANIUM COMPOUNDS; URANIUM FLUORIDES; URANIUM OXIDES; 050400* - Nuclear Fuels- Feed Processing; 360201 - Ceramics, Cermets, & Refractories- Preparation & Fabrication

Citation Formats

Hart, J E, Shuck, D L, and Lyon, W L. Production of uranium dioxide. United States: N. p., 1977. Web.
Hart, J E, Shuck, D L, & Lyon, W L. Production of uranium dioxide. United States.
Hart, J E, Shuck, D L, and Lyon, W L. Tue . "Production of uranium dioxide". United States.
@article{osti_5386597,
title = {Production of uranium dioxide},
author = {Hart, J E and Shuck, D L and Lyon, W L},
abstractNote = {A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF/sub 6/) to ceramic-grade uranium dioxide (UO/sub 2/) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF/sub 6/ with steam in a first fluidized bed, preferably at about 550/sup 0/C, to form solid intermediate reaction products UO/sub 2/F/sub 2/, U/sub 3/O/sub 8/ and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF/sub 4/). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630/sup 0/C. The second intermediate reaction product including uranium dioxide (UO/sub 2/) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650/sup 0/C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein a mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO/sub 2/ and increase the oxygen-uranium ratio to about 2.25.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1977},
month = {10}
}